The objectives of this research are to examine the effects of an early, postnatal nutritional insult of protein-deficiency or calorie-deficiency on the physical growth, skeletal maturation and dental development of a nonhuman primate. Because all living primates share a growth curve that differs from the growth curves of other mammals in showing a long period of slow growth during childhood, it is believed that the results of this experimental malnutrition will be particularly relevant to understanding the effects of an early insult of protein-calorie malnutrition on human growth and development. Laboratory-reared, capucin monkeys (Cebus albifrons) were fed "good" diets, calorie-deficient diets or protein-deficient diets for a twenty week period beginning at eight weeks of age. At twenty-eight weeks of age, all animals were rehabilitated to a good diet. Anthropometric measurements and whole-body radiographs have been taken of the experimental animals at regular interval. The longitudinal series of anthropometric measurements and skeletal dimensions taken from the radiographs will be analyzed in order to investigate catch-up growth in the rehabiliated monkeys. The longitudinal series of whole-body radiographs will also be used to investigate skeletal maturation in the rehabilitated animals and the effects of an early insult on dental development. Further studies in progress will examine the effects of an earlier nutritional insult between two and eight weeks of age.